Rock The Boat Audio

Video: How To Connect Your Boat Stereo To A Marine Amplifier

By Matt Champneys

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Connecting your marine stereo to an amplifier is simple, but there are a few different ways to go about it. In this video we will discuss those options and the pros and cons of each.

The most common method is to use the RCA pre-amp output jacks on the back of the stereo. Some are embedded right in the chassis of the stereo like this. Others are on wires extending out from the stereo like this. You can identify them by the red and white color coding used to separate right and left stereo channels. Some stereos will also have RCA inputs so be careful that you don't get them mixed up.

You will use an RCA cable like this one to connect the outputs of the stereo to the inputs on the amplifier.

The pre-amp outputs provide a low voltage, but very clean audio signal to the amplifier. That is the main advantage to using them.

The number of pre-amp outputs will vary from stereo to stereo. Most will have at least one set, but they can have up to 3 or even more pairs. A stereo with 3 pairs of outputs will usually have a pair for the front speakers, a pair for the rear speakers and a pair for subwoofers.

Likewise, amplifiers will have varying numbers of inputs depending on how many channels the amp has. If the number of outputs match the number of inputs, your job is easy. Just use as many RCA cables as you need to connect them up.

If the number of outputs don't match the number of inputs then you've got some decisions to make. There is no requirement to use all of the pre-amp outputs. If you are using a 2 channel amp, then just use the front outputs. If you are using a 4 channel amp, then just use the front and rear outputs. Only use a subwoofer output if you are using a subwoofer.

But what if your stereo has fewer outputs than the amp has inputs? Many amplifiers will have an input mode switch. Say your stereo only has one pair of outputs, but you want to connect to a 4 channel amp with 4 inputs. Connect your one rca cable to channels 1 and 2 on the amp. Switch the input mode on the amp to 2 channel. The audio signal input from channels 1 and 2 will then be equally distributed to channels 3 and 4 as well.

No input mode switch? Then you'll have to resort to using RCA splitters like this to match the number of outputs to the number of inputs.

Consider that how you arrange the outputs and inputs may affect how much control you have over the sound from the stereo face. For example, fade control adjusts the volume between front speakers and rear speakers, but if you only use the front pre-amp outputs and not the rear, then fade control won't work.

What if your stereo has no pre-amp outputs at all? You'll have to use a different method. Use the powered speaker outputs as your audio signal source. Using a higher powered audio signal can introduce a small amount of distortion and static into the final audio output, which is the main drawback of this method. Most people will find it acceptable, but it might bother you if you are picky about your sound quality.

You'll need to pick up some RCA connectors like these to put on the ends of the speaker wires attached to the head unit. Then you can plug then into the inputs on the amplifier.

A higher power signal can overdrive your amp and cause damage so you'll need to adjust some settings to compensate. Some amps will have an audio input switch that will allow you to switch between high and low power. You'll want to select the high power mode. Most amps will also have one or more gain controls. You can dial that down compensate for the higher power signal.

Is there ever an advantage to using the powered speaker outputs instead of pre-amp outputs? Well, if your stereo only has 1 pair of pre-amp outputs and you'd really like to preserve the fade control, then using the front and rear powered speaker outputs will let you do that.

But all things being equal, you will usually want to use the pre-amp outputs instead for the best sound quality.

Thanks for watching!

In another video we will talk about how to optimize the gain control on your amp for the best sound quality.